There are now thought to be more than 500,000 people aged 90 or over and numbers are rising. Photograph: Daniel Berehulak/Getty Images

The number of people over 100 living in the UK has increased nearly fivefold in 30 years as better medical treatments, housing, nutrition and living standards, together with a decline in smoking, significantly improved the chances of surviving to a very old age, the Office for National Statistics said on Friday.

There were an estimated 13,350 centenarians in 2012 – a 73% increase in a decade – and 660 of them were over 105, according to the figures. Though this still represents a very small proportion of the overall population, it provides another stark indication of the mounting problems facing successive governments as they struggle to finance demands on the welfare state including a rising state pension bill.

The number of very old people is rising faster among men than women as the traditional gender gap in life expectancy narrows. There are now thought to be more than 500,000 people aged 90 or over and the numbers are rising more steeply after a dip in 2008, which reflected the fall in births during the first world war. Interestingly, 1918 saw the lowest number, but this was followed by a postwar baby boom.

The ONS says the UK, with 21 centenarians per 100,000 population, still lags behind countries such as Japan with 40 and France with 30, the highest proportion in Europe. Russia has just over four per 100,000, while China and India have lower figures still.

In 2012, nearly three-quarters of the UK's people aged 90 and over were women, although the balance is shifting. The gender ratio for centenarians fell from 828 women for every 100 men in 2002 to 588 in 2012. The latest life expectancy at birth is 82.6 for women and 78.7 for men.

The largest increases of people aged 90-plus have been in England and Wales, with the smallest in Northern Ireland. Scotland and Northern Ireland also have higher male mortality in the age group.